Manipulation of particles by size in an aqueous suspension or slurry may have widespread applications. Particles may be concentrated or retained for subsequent processing, diagnostic testing, or storage, e.g., algae spore concentration, circulating tumor cell (CTC) enrichment, whole blood processing, and the like. Undesirable particles may be separated from other components, e.g., extraction of antibiotics from fermentation broth, DNA purification, blood plasma cleansing, wastewater treatment, and the like.
Macroscopic methods, such as dead-end filtration and centrifugation may be time-consuming, may be unsuited to continuous processing, may cause the particles to be exposed to undesirable conditions such as large shear forces or prolonged contact with foreign surfaces, may cause filter fouling, and may require bulky, expensive equipment. Tangential flow or cross-flow filtration may not be cost-effective for many applications, particularly for one-time use requirements due to contamination or sterility concerns, e.g., blood cell separation.
Continuous microfluidic techniques may include active devices using magnetic, acoustic, dielectrophoretic, or other forces, but may require complex equipment or undesirable solution preparation steps, and may also be low throughput. Passive techniques may use microfluidic phenomena, such as deterministic lateral displacement (DLD), the Zweifach-Fung effect, pinched flow fraction, hydrodynamic filtration, etc., or inertial focusing such as in the tubular pinch effect and dean flow fractionation. However, microfluidics may be problematic for small particles below ˜5 μm, leading to the use of high pressures which may damage sensitive particles, such as platelets or cells. Microfluidic devices may require computational fluid dynamics (CFD) simulations, particularly for manipulating particles of a specific size. Such CFD techniques may be complex, time consuming, and may be limited by particle heterogeneity, especially for biological applications, as well as the constraints of finite computing power.
One area in need of improved particle separation technique is blood cell separation. Over 30 million individual units of the three main blood components—red blood cells (RBCs), platelet concentrate (PC), and plasma—are transfused in the U.S. every year. Nearly 70% of all whole blood (WB) donated in the U.S. is collected on mobile blood drives, often more than 100 miles away from the centralized blood banking facilities. Because of the significant differences in optimal storage conditions (1-6° C. for RBCs, 22±2° C. for platelets, −18° C. for plasma), WB should be quickly separated. The centrifugation-based equipment currently used to process WB into blood components may be undesirably expensive, bulky, laborious, and energy-intensive, especially for mobile blood collection coaches.
Further, high-speed centrifugation for WB separation may subject blood cells to damaging physical forces, may require two stages of centrifugation to separate WB into packed RBCs and platelet-rich plasma (PRP), followed by PRP into PC and platelet-poor plasma (PPP).
The present application appreciates that manipulation of particles by size in an aqueous suspension or slurry may be a challenging endeavor.